At present, there are many types of cancer screening methods—from traditional imaging and tumor marker blood tests to the more recent “liquid biopsy” technologies. Each method has its own uses and limitations. To choose the most suitable screening option, it’s important to first understand their principles, accuracy, and target users.

What are the common cancer screening methods?

Tumor Markers (Cancer Marker / Tumor Marker)
Doctors often use blood tests to evaluate tumor markers, which help assess cancer risk, monitor treatment responses, or detect recurrence. These markers are specific substances found in blood or body fluids that can be produced by cancer cells or the body’s response to tumors—for example, alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA).
However, tumor markers can be affected by other factors such as inflammation, disease, or lifestyle, leading to false-positive or false-negative results. Therefore, marker levels alone are not sufficient for diagnosis and are mainly used as preliminary screening and monitoring tools.

Imaging Tests (X-ray, Ultrasound, CT, MRI, PET-CT)
These are traditional yet essential diagnostic methods that visualize tumor size and location inside the body. Different types of imaging are suited for different organs and conditions:

• X-ray, Ultrasound: Common for preliminary checks of the chest, abdomen, and breasts.

• CT, MRI: Provide detailed cross-sectional images for further tumor evaluation.

• PET-CT: Uses radioactive tracers to show tumor activity, often used for staging and assessing metastasis.
  Do note that imaging tests typically require a tumor to reach about 0.5–1 cm for reliable detection. Smaller tumors may be missed, and some tests involve radiation exposure or higher costs.

Blood Tests (cfDNA/ctDNA, microRNA, CancerSEEK)
“Liquid biopsy” analyzes substances released by tumors into the blood.

• ctDNA focuses on fragments of tumor DNA;

• mRNA tracks gene expression signals;

• CancerSEEK combines genetic mutations and protein markers.
  In research, CancerSEEK has shown about 70% sensitivity and 99% specificity for eight types of cancer. These advanced tests are mainly for high-risk screening and research, with real-world clinical use still evolving.

Is ctDNA screening more suitable for me?

ctDNA (circulating tumor DNA) testing uses next-generation sequencing (NGS) and AI analysis to detect DNA fragments with as little as 0.25% mutation signals. Accuracy ranges from 92–99%, excelling in monitoring minimal residual disease (MRD) and predicting recurrence.

Who may benefit from ctDNA screening?

• Individuals with family or genetic cancer risk

• Those seeking highly specific early detection

• Post-surgery patients monitoring for recurrence (under medical consultation)

• People wishing to reduce frequent radiation exposure

What are the advantages of ctDNA testing? 

• Requires only a small blood sample; non-invasive and simple

• Detects ultra-early signals (up to 3–5 years earlier), covering 38+ types of male cancers and 42+ types of female cancers (including lung, colon, breast, liver, and prostate)

• High accuracy and specificity, with AI-assisted analysis supporting precision treatment

• Suitable for multi-cancer risk assessment and can complement other screening methods

What cancers are detectable by ctDNA:
Breast, stomach, nasopharyngeal, colorectal, lung, pancreatic, head and neck, liver, and cervical cancers, among others (for example, SPOT-MAS can detect up to 10 cancer types).
mRNA testing can act as a complementary tool, targeting tumors as small as 0.2 cm, providing enhanced accuracy when used together with ctDNA screening.

Human Health offers several cancer risk assessment programs available on its online store, including:

• SPOT-MAS Women 10 Types Multi-Cancer Early Detection (HCDNA01): HK$3,860 (original HK$9,650) 

• SPOT-MAS Men 8 Types Multi-Cancer Early Detection (HCDNA02): HK$3,160 (original HK$7,900)

All programs can be purchased through the Human Health eShop.
For inquiries, please call the service hotline at 2397 2111.

Although ctDNA testing is more expensive than traditional tumor marker tests, it remains moderately priced compared with multiple high-end imaging procedures. It stands out as a high-precision screening option offering an additional “blood test for cancer detection” method, capable of identifying early cancer risk and guiding timely medical follow-up and treatment—particularly valuable for high-risk individuals. If in doubt, it is recommended to consult your doctor before making a decision.